阅读说明：本技术 一种微波气体高温结晶金刚石单晶的工艺 (Process for crystallizing diamond single crystal at high temperature by microwave gas ) 是由 张新峰 姜再兴 龙安泽 王炜 于 2020-04-21 设计创作，主要内容包括：本发明涉及人工金刚石单晶合成应用技术领域,且公开了一种微波气体高温结晶金刚石单晶的工艺,包括以下步骤：1)制备金刚石合成柱；2)合成金刚石；3)后续检测。该微波气体高温结晶金刚石单晶的工艺,通过按照步骤1)和步骤2)来进行金刚石合成柱的制备与金刚石的合成,且其均分为不同批次并进行标记,标记完成后将制得的金刚石合成柱按照步骤2)放置在微波加热装置内部进行加热和加压操作,当加热温度为800℃到1000℃时,且其内部处于标准大气压状态时可制得高品质人造金刚石单晶,达到了合成简便且合成质量较好的效果,从而有效的解决了现如今的人工金刚石单晶合成过程较为复杂且合成的品质也较为一般的问题。(The invention relates to the technical field of synthetic application of artificial diamond single crystals, and discloses a process for crystallizing diamond single crystals at high temperature by microwave gas, which comprises the following steps: 1) preparing a diamond synthetic column; 2) synthesizing diamond; 3) and (5) subsequent detection. According to the process for crystallizing the diamond single crystal at high temperature by using microwave gas, the preparation of the diamond synthetic column and the synthesis of diamond are carried out according to the step 1) and the step 2), the diamond synthetic column is divided into different batches and marked, the prepared diamond synthetic column is placed in a microwave heating device according to the step 2) after the marking is finished, heating and pressurizing operations are carried out, when the heating temperature is 800-1000 ℃, and the interior of the diamond synthetic column is in a standard atmospheric pressure state, a high-quality artificial diamond single crystal can be prepared, the effects of simple synthesis and good synthesis quality are achieved, and the problems that the synthesis process of the existing artificial diamond single crystal is complex and the synthesis quality is general are effectively solved.)

1. A process for microwave gas high-temperature crystallization of diamond single crystals is characterized by comprising the following steps:

1) preparing a diamond synthetic column, moulding the diamond-forming layer into a cylindrical structure with a cylindrical shape and an equal size, performing batch operation on the cylindrical structure, placing the diamond-forming layer and seed crystals for crystallization into the cylindrical diamond synthetic column in batches, sleeving a carbon tube and a dolomite outer layer in the cylindrical diamond synthetic column, attaching carbon plates to the top and the bottom of the high-purity magnesium oxide column after sleeving, sealing to obtain the diamond synthetic column after sealing, and marking the diamond synthetic column correspondingly;

2) synthesizing diamond, placing the diamond synthesizing column obtained in the step 1) in a microwave heating device, starting the microwave heating device after the placement is finished, simultaneously introducing carbon-containing gas-methane (CH 4) and hydrogen into the device through a transmission pipeline, conveying the carbon-containing gas and the hydrogen into a vacuumized reaction chamber, wherein the reaction chamber is in a low-pressure state, the microwave heats the gas, when the internal temperature of the microwave heating device is heated to 800-1000 ℃, nitrogen, carbon and methane are added, then the temperature in the device chamber is increased, the temperature is 1100-, at the moment, the nitrogen can be closed when the pressure of the cavity reaches the standard atmospheric pressure, and finally the granular diamond or the small-sized sheet diamond is obtained and taken out;

3) subsequent detection, namely putting the diamond synthetic columns obtained in the step 2) into a microwave heating device in batches, carrying out repetitive operation according to the step 3), carrying out corresponding labeling and recording on the obtained granular diamond or small-sized flaky diamond according to the labels of different batches on the step 2), detecting the crystal form, the transparency, the color, the granularity, the magnetic susceptibility and the thermal shock intensity of the diamond after the recording is finished, wherein the detection standard is the existing artificial diamond detection standard, the grade of the diamond single crystal can be preliminarily judged by observing the color, the transparency, the dent, the carbon deposition and the polycrystal of the surface of the diamond single crystal, the detection is carried out by 20 times, the grade of the diamond single crystal is finally confirmed by observing whether the growth lines on the surface of the diamond single crystal are flat or not and whether cracks exist or not through a 20 times magnifier is used for detection, and the grade of the diamond single crystal is finally confirmed by detecting, and (5) after the detection is finished and the product is qualified, the product can be delivered out of the factory.

2. A microwave gas high temperature crystallization diamond monocrystal process according to claim 1, characterized in that: the diamond synthetic column in the step 1) is cylindrical in shape, high-purity graphite is filled in the diamond synthetic column, the purity of the graphite is more than or equal to 99%, the high-purity graphite is in a layer-by-layer stacking state, and the diamond synthetic column in the step 1) is stored at a normal temperature after preparation and labeling are finished.

3. A microwave gas high temperature crystallization diamond monocrystal process according to claim 1, characterized in that: the thickness of the diamond generation layer in the step 1) is 10-30 mm, the thickness of the inner wall of the diamond synthetic column prepared in the step 1) is 0.8-5 mm, and the label point of the diamond synthetic column in the step 1) is the top of the front face of the diamond synthetic column.

4. A microwave gas high temperature crystallization diamond monocrystal process according to claim 1, characterized in that: and in the step 2), after the synthesis of the diamond is finished, waiting for the temperature in the diamond to be reduced and stopping heat supply, stopping heating for 10-20 min, starting pressure relief after the heat stopping time is finished, finishing the synthesis of the diamond when the pressure in the diamond is reduced to 0MPa and the temperature is reduced to room temperature, and finally taking out the diamond and carrying out the detection in the step 3).

5. A microwave gas high temperature crystallization diamond monocrystal process according to claim 1, characterized in that: the processing temperature of the seed crystal is controlled to be about 1100-1150 ℃, the pressure is controlled to be about 135Torr, the stability of the temperature is continuously ensured, the temperature of the furnace chamber of the microwave heating device is higher, the microwave heating device needs to be cooled by pure water with the conductivity less than 1, and the temperature of inlet water needs to be controlled within 23-25 ℃ to ensure the cooling effect.

Technical Field

The invention relates to the technical field of synthetic application of artificial diamond single crystals, in particular to a process for crystallizing diamond single crystals at high temperature by microwave gas.

Background

Diamond is commonly called diamond, namely the original body of diamond single crystal, which is a mineral composed of carbon elements and is an allotrope of the carbon elements, the diamond is the hardest substance naturally existing in nature, the Mohs hardness is 10, the new Mohs hardness is 15, the microhardness is 10000kg/mm2, the microhardness is 1000 times higher than that of quartz and 150 times higher than that of corundum, the diamond hardness has directionality, the hardness of octahedral crystal face is greater than that of rhombic dodecahedral crystal face, the hardness of rhombic dodecahedral crystal face is greater than that of hexahedral crystal face, the application of the diamond is very wide, the graphite can form the artificial diamond at high temperature and high pressure, it also belongs to precious gemstones, and the artificial diamond single crystal belongs to an artificially synthesized diamond single crystal, and is a polycrystalline diamond single crystal formed by polymerizing diamond single crystals with the diameters of 10 to 30 nanometers.

The early artificial diamond single crystal enters the diamond single crystal due to nitrogen atoms in the air to be in a light syrup color, the existing produced artificial diamond single crystal has no difference from a natural diamond single crystal in appearance, the molecular structure of the artificial diamond single crystal is not a complete octahedral structure of the natural diamond single crystal but a complex structure due to different generation environments, so that a phosphorescence phenomenon can be generated, the synthetic diamond single crystal and the processing cost are still high in the past, the requirements on equipment, technology, process and the like are still high, a small amount of synthetic diamond single crystals are put on the market in the world at present, but the synthetic diamond single crystals have no price advantage, but with the development of science and technology, the existing artificial diamond single crystals have commercial value, the application of the artificial diamond single crystals is very wide at present, and the method for artificially synthesizing the diamond single crystals at present has been researched, the method mainly uses CVD and a temperature difference method, but the synthesis process of the existing artificial diamond single crystal is complex, the synthesis quality is general, and the social requirements are difficult to meet, so a process for crystallizing the diamond single crystal at high temperature by microwave gas is provided to solve the problems.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a process for crystallizing diamond single crystals at high temperature by microwave gas, which has the advantages of simple synthesis, good synthesis quality and the like, and solves the problems that the synthesis process of the existing artificial diamond single crystals is complex and the synthesis quality is general.

(II) technical scheme

The invention aims to solve the technical problem of providing a process for crystallizing diamond single crystals at high temperature by microwave gas, which comprises the following steps:

1) preparing a diamond synthetic column, moulding the diamond-forming layer into a cylindrical structure with a cylindrical shape and an equal size, performing batch operation on the cylindrical structure, placing the diamond-forming layer and seed crystals for crystallization into the cylindrical diamond synthetic column in batches, sleeving a carbon tube and a dolomite outer layer in the cylindrical diamond synthetic column, attaching carbon plates to the top and the bottom of the high-purity magnesium oxide column after sleeving, sealing to obtain the diamond synthetic column after sealing, and marking the diamond synthetic column correspondingly;

2) synthesizing diamond, placing the diamond synthesizing column obtained in the step 1) in a microwave heating device, starting the microwave heating device after the placement is finished, simultaneously introducing carbon-containing gas-methane (CH 4) and hydrogen into the device through a transmission pipeline, conveying the carbon-containing gas and the hydrogen into a vacuumized reaction chamber, wherein the reaction chamber is in a low-pressure state, the microwave heats the gas, when the internal temperature of the microwave heating device is heated to 800-1000 ℃, nitrogen, carbon and methane are added, then the temperature in the device chamber is increased, the temperature is 1100-, at the moment, the nitrogen can be closed when the pressure of the cavity reaches the standard atmospheric pressure, and finally the granular diamond or the small-sized sheet diamond is obtained and taken out;

3) subsequent detection, namely putting the diamond synthetic columns obtained in the step 2) into a microwave heating device in batches, carrying out repetitive operation according to the step 3), carrying out corresponding labeling and recording on the obtained granular diamond or small-sized flaky diamond according to the labels of different batches on the step 2), detecting the crystal form, the transparency, the color, the granularity, the magnetic susceptibility and the thermal shock intensity of the diamond after the recording is finished, wherein the detection standard is the existing artificial diamond detection standard, the grade of the diamond single crystal can be preliminarily judged by observing the color, the transparency, the dent, the carbon deposition and the polycrystal of the surface of the diamond single crystal, the detection is carried out by 20 times, the grade of the diamond single crystal is finally confirmed by observing whether the growth lines on the surface of the diamond single crystal are flat or not and whether cracks exist or not through a 20 times magnifier is used for detection, and the grade of the diamond single crystal is finally confirmed by detecting, and (5) after the detection is finished and the product is qualified, the product can be delivered out of the factory.

Preferably, the diamond synthetic column in the step 1) is cylindrical in shape, high-purity graphite is filled in the diamond synthetic column, the purity of the graphite is more than or equal to 99%, the high-purity graphite is in a layer-by-layer stacking state, and the diamond synthetic column in the step 1) is stored at a normal temperature after preparation and labeling are finished.

Preferably, the thickness of the diamond-forming layer in step 1) is 10 to 30mm, the thickness of the inner wall of the diamond synthesis column prepared in step 1) is 0.8 to 5mm, and the reference point of the diamond synthesis column in step 1) is the top of the front surface of the diamond synthesis column.

Preferably, after the diamond synthesis in the step 2) is finished, the temperature in the diamond is waited to be reduced and heat supply is stopped, the heat stopping time is 10min to 20min, pressure relief is started after the heat stopping time is finished, when the pressure in the diamond is reduced to the standard and the temperature is reduced to the room temperature, the diamond synthesis can be finished, and finally the diamond is taken out and the detection in the step 3) is carried out.

Preferably, the temperature of the seed crystal treatment is controlled to be about 1100-1150 ℃, the pressure is controlled to be about 135Torr, the stability of the temperature is continuously ensured, the temperature of the furnace chamber of the microwave heating device is higher, the microwave heating device needs to be cooled by pure water with the conductivity less than 1, and the temperature of the inlet water needs to be controlled within 23-25 ℃ to ensure the cooling effect.

(III) advantageous effects

Compared with the prior art, the invention provides a process for crystallizing diamond single crystal at high temperature by microwave gas, which has the following beneficial effects:

1. according to the process for crystallizing the diamond single crystal at high temperature by using microwave gas, the preparation of the diamond synthetic column and the synthesis of diamond are carried out according to the step 1) and the step 2), the diamond synthetic column is divided into different batches and marked, the prepared diamond synthetic column is placed in a microwave heating device according to the step 2) after the marking is finished, heating and pressurizing operations are carried out, when the heating temperature is 800-1000 ℃, and the interior of the diamond synthetic column is in a standard atmospheric pressure state, high-quality artificial diamond single crystal can be prepared, the effects of simplicity and convenience in synthesis and good synthesis quality are achieved, the whole process is very simplified through the process, artificially synthesized diamond can be quickly obtained, the process is good in practicability, and the process is convenient to popularize and use.

2. The process for crystallizing the diamond single crystal at high temperature by microwave gas comprises the steps of putting diamond synthesis columns obtained in the step 1) into a microwave heating device in batches, carrying out repetitive operation according to the step 2), effectively avoiding the problem of low synthesis efficiency of the artificial diamond single crystal during synthesis, detecting the crystal form, transparency, color, granularity, magnetic susceptibility and thermal shock strength of diamond, wherein the detection standard is the existing artificial diamond detection standard, and the artificial diamond single crystal can leave a factory after detection is finished and qualified, so that the factory quality of the artificial diamond single crystal can be effectively enhanced, and further the quality requirement of subsequent processing can be met And also has more general problems.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A process for microwave gas high-temperature crystallization of diamond single crystals comprises the following steps:

1) preparing a diamond synthetic column, moulding the diamond synthetic column to form a cylindrical structure with the same shape and size, carrying out batch operation on the cylindrical structure, putting the diamond synthetic column and seed crystals for crystallization into the cylindrical diamond synthetic column in batches, sleeving a carbon tube and a dolomite outer layer in the cylindrical structure, attaching carbon plates to the top and the bottom of the high-purity magnesium oxide column for sealing after the sleeving is finished, obtaining the diamond synthetic column after the sealing is finished, and correspondingly marking the diamond synthetic column, wherein the diamond synthetic column in the step 1) is cylindrical in shape, high-purity graphite is filled in the diamond synthetic column in the step 1), the purity of the graphite is more than or equal to 99 percent, the high-purity graphite is in a layer-by-layer stacking state, the diamond synthetic column in the step 1) is prepared and stored in a normal temperature state after the labeling is finished, and the thickness of the diamond synthetic layer in the step 1) is 10-30 mm, the thickness of the inner wall of the diamond synthetic column prepared in the step 1) is 0.8-5 mm, and the label point of the diamond synthetic column in the step 1) is the top of the front surface of the diamond synthetic column;

2) synthesizing diamond, placing the diamond synthesizing column obtained in the step 1) in a microwave heating device, starting the microwave heating device after the placement is finished, simultaneously introducing carbon-containing gas-methane (CH 4) and hydrogen into the device through a transmission pipeline, conveying the carbon-containing gas and the hydrogen into a vacuumized reaction chamber, wherein the reaction chamber is in a low-pressure state, the microwave heats the gas, when the internal temperature of the microwave heating device is heated to 800-1000 ℃, nitrogen, carbon and methane are added, then the temperature in the device chamber is increased, the temperature is 1100-, at the moment, the nitrogen can be closed when the pressure of the cavity reaches the standard atmospheric pressure, and finally the granular diamond or the small-sized sheet diamond is obtained and taken out;

3) subsequent detection, placing the diamond synthetic columns obtained in the step 2) into a microwave heating device in batches, performing repeated operation according to the step 3), correspondingly labeling and recording the obtained granular diamond or small-sized sheet diamond according to the marks of different batches in the step 2), detecting the crystal form, transparency, color, granularity, magnetic susceptibility and thermal shock strength of the diamond after recording, wherein the detection standard is the existing artificial diamond detection standard, and leaving the factory after detection and qualification, when the diamond synthesis in the step 2) is finished, waiting for the temperature in the diamond to be reduced and stopping heat supply, stopping heat supply for 10-20 min, and starting pressure relief after the heat stopping time is finished, when the pressure in the diamond is reduced to normal atmospheric pressure and the temperature is reduced to room temperature, the synthesis of the diamond can be completed, and finally the diamond is taken out and the detection of the step 3) is carried out.

The invention has the beneficial effects that: the process for crystallizing diamond single crystals at high temperature by microwave gas comprises the steps of 1) and 2) preparing diamond synthetic columns and synthesizing diamonds, uniformly dividing the diamond synthetic columns into different batches and marking the diamond synthetic columns, placing the prepared diamond synthetic columns in a microwave heating device according to the step 2) for heating and pressurizing operation after marking is finished, and when the heating temperature is 800-1000 ℃ and the interior of the diamond synthetic columns is in a standard atmospheric pressure state, preparing high-quality artificial diamond single crystals so as to achieve the effects of simple synthesis and good synthesis quality, the whole process is very simple, artificially synthesized diamonds can be quickly obtained, the process is good in practicability and convenient to popularize and use, and the process for crystallizing diamond single crystals at high temperature by microwave gas comprises the steps of 1) placing the diamond synthetic columns in the microwave heating device in batches and repeatedly operating according to the step 2), the problem that the synthesis efficiency is low when the artificial diamond single crystal is synthesized can be effectively avoided, the crystal form, the transparency, the color, the granularity, the magnetic susceptibility and the thermal shock strength of the diamond are detected, the detection standard is the existing artificial diamond detection standard, the artificial diamond single crystal can leave the factory after the detection is finished and qualified, the factory-leaving quality of the artificial diamond single crystal can be effectively enhanced, and further the quality requirement of subsequent processing can be met, the whole process flow of the high-temperature crystallization diamond single crystal is very simple, the quality and the form of the synthesized diamond are good, and meanwhile, the artificial diamond single crystal can leave the factory through the multiple detection of the step 3) after the synthesis is finished, so that the problems that the existing artificial diamond single crystal synthesis process is complex and the synthesis quality is general are effectively solved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.